One major objective of this project is to extend current studies of the effect of dopamine (DA) agonists such as apomorphine on serum prolectin (PRL) and growth hormone in acute and chronic schizophrenics and patients with affective psychoses. Our studies will relate the magnitude of the hormone response to two doses of the DA agonist to duration of illness, type of psychopathology, and clinical response to a fixed oral dose of neuroleptics. The data will be examined for differences in DA receptor sensitivity between patients and controls. Preliminary findings of high incidence of depression in manic and schizoaffective, primarily manic patients given apomorphine will be further investigated. A second line of inquiry will focus on the effects of acute and chronic administration of neuroleptics on serum PRL in schizophrenics in relation to blood levels of neuroleptics as determined by radioreceptor assay and to clinical response. Two low doses of CPZ8 12.5 and 25 mg i.m.) will be given to schizophrenics and controls to determine if there is a difference in sensitivity of DA receptors for the two groups. Rat endocrine studies will focus on the role of serotonin (5-HT) in stimulating PRL secretion. Our objective is to study the supersensitivity which develops following PCPA, an inhibitor of 5-HT synthesis, or "spaced injections" of 5-HT agonists such as the indole hallucinogens. The hypothesis that inhibition of raphe firing causes this will be explored. The effect of PCPA and spaced injections of 5-MeODNT on 5-HT receptors in the hypothalamus will be studied. The role of the medial raphe in rat PRL secretion will be studied through lesion and biochemical studies.